1. Field of the Invention
The present invention relates in general to self powered sensors and methods for providing power to circuits and sensors embedded in systems adapted for use in hostile or remote environments.
2. Description of the Background Art
Wireless sensor suites deployed in remote and inaccessible areas need long operating lifetimes as battery monitoring and replacement is often cost-prohibitive. Such applications include long-term health monitoring of tactical missiles, industrial equipment, buildings, etc. In addition to efforts on increasing the lifetime of the conventional electrochemical batteries currently in use, work is being done on alternative power solutions. These approaches include powering the sensor suite using energy scavenged from ambient vibrations, solar radiation, tidal energy, etc. Additionally, alternative fuel-based power sources such as fuel cells and radioisotope power generators have also been proposed. All these solutions look promising, but are yet to be adopted widely.
An alternate approach to increasing the lifetime of battery powered sensor suites employs zero-power sensors, which can be passive or self-powered. Such self-powered sensors can wake-up the rest of the sensor node when required, conserving the battery power for emergency computations and communications. Self-powered sensors based on passive fiber-optics have been demonstrated, but fiber-optic based approaches require complicated signal processing for conversion of optical signals to electrical signals.
Fissile material detectors sensing neutrons and/or γ-rays can be divided into passive and active types. The active detectors are very sensitive but may consume significant power for operation and are thus unsafe for portable applications due to the interrogating irradiation. In contrast, passive detectors are low power consuming and small in size, but their sensitivity is often limited.
In view of the foregoing, a need remains for a method and apparatus for increasing the lifetime of powered sensor suites.
A need also remains for a self-powered fissile material detector having very high sensitivity.